# Define here the models for your spider middleware
#
# See documentation in:
# https://docs.scrapy.org/en/latest/topics/spider-middleware.html
import base64
import random
import time
from encodings.utf_16 import encode

from scrapy.http import HtmlResponse
from selenium import webdriver

from scrapy import signals

# useful for handling different item types with a single interface
from myspider.settings import USER_AGENT_LIST, PROXY_LIST


class MyspiderSpiderMiddleware:
    # Not all methods need to be defined. If a method is not defined,
    # scrapy acts as if the spider middleware does not modify the
    # passed objects.

    @classmethod
    def from_crawler(cls, crawler):
        # This method is used by Scrapy to create your spiders.
        s = cls()
        crawler.signals.connect(s.spider_opened, signal=signals.spider_opened)
        return s

    def process_spider_input(self, response, spider):
        # Called for each response that goes through the spider
        # middleware and into the spider.

        # Should return None or raise an exception.
        return None

    def process_spider_output(self, response, result, spider):
        # Called with the results returned from the Spider, after
        # it has processed the response.

        # Must return an iterable of Request, or item objects.
        for i in result:
            yield i

    def process_spider_exception(self, response, exception, spider):
        # Called when a spider or process_spider_input() method
        # (from other spider middleware) raises an exception.

        # Should return either None or an iterable of Request or item objects.
        pass

    def process_start_requests(self, start_requests, spider):
        # Called with the start requests of the spider, and works
        # similarly to the process_spider_output() method, except
        # that it doesn’t have a response associated.

        # Must return only requests (not items).
        for r in start_requests:
            yield r

    def spider_opened(self, spider):
        spider.logger.info("Spider opened: %s" % spider.name)


class MyspiderDownloaderMiddleware:
    # Not all methods need to be defined. If a method is not defined,
    # scrapy acts as if the downloader middleware does not modify the
    # passed objects.

    @classmethod
    def from_crawler(cls, crawler):
        # This method is used by Scrapy to create your spiders.
        s = cls()
        crawler.signals.connect(s.spider_opened, signal=signals.spider_opened)
        return s

    def process_request(self, request, spider):
        # Called for each request that goes through the downloader
        # middleware.

        # Must either:
        # - return None: continue processing this request
        # - or return a Response object
        # - or return a Request object
        # - or raise IgnoreRequest: process_exception() methods of
        #   installed downloader middleware will be called
        return None

    def process_response(self, request, response, spider):
        # Called with the response returned from the downloader.

        # Must either;
        # - return a Response object
        # - return a Request object
        # - or raise IgnoreRequest
        return response

    def process_exception(self, request, exception, spider):
        # Called when a download handler or a process_request()
        # (from other downloader middleware) raises an exception.

        # Must either:
        # - return None: continue processing this exception
        # - return a Response object: stops process_exception() chain
        # - return a Request object: stops process_exception() chain
        pass

    def spider_opened(self, spider):
        spider.logger.info("Spider opened: %s" % spider.name)


# 定义随机UserAgent中间件
class RandomUserAgent(object):
    def process_request(self, request, spider):

        ua = random.choice(USER_AGENT_LIST)

        request.headers['User-Agent']  = ua

        # print(request.headers['User-Agent'])

# 定义随机IP代理
class RandomProxy(object):
    def process_request(self, request, spider):
        pass
        # proxy = random.choice(PROXY_LIST)
        # if 'name_pwd' in proxy:
        #     # 对帐号密码进行base64编码
        #     b64_up = base64.b64encode(proxy['name_pwd'].encode())
        #     # 设置认证
        #     request.headers['Proxy-Authorization'] = 'Basic ' + b64_up.decode()
        #     # 设置代理
        #     request.meta['proxy'] = proxy['ip_port']
        # else:
        #     # 设置代理
        #     request.meta['proxy'] = proxy['ip_port']
        #     print(request.meta['proxy'])

# 自动化 selenium 爬虫
class SeleniumMiddleware(object):
    def process_request(self, request, spider):
        pass
        # url = request.url
        #
        # if 'daydata' in url:
        #     driver = webdriver.Chrome()
        #
        #     driver.get(url)
        #     time.sleep(3)
        #     data = driver.page_source
        #
        #     driver.close()
        #     #  创建对象
        #     res = HtmlResponse(url=url, body=data, encoding='utf-8', request=request)
        #
        #     return res


